TM 9-2320-363-102-21. OPERATE SLIDING FIFTH WHEEL (M915A2). The M915A2 is designed to be used with M871,M872, and M1062 semitrailers only. Other semitrail-ers may cause equipment damage.Trailer must be blocked and trailer brakes locked toprevent damage to tractor or trailer by uncontrolledsliding of fifth wheel.If towing M872 trailer, rear mud flaps must beremoved and stowed in brackets provided. Failureto do so will cause equipment damage. The tractor/trailer combination is not capable ofturning more than a 90° angle.The M915A2, M916A1, and M916A2 truck tractorshave the capability to turn greater than 90°. Caremust be taken to avoid hitting semitrailer with trac-tor when turning more than 90°. Operator must use caution when cresting hillswhich cause the truck tractor to have a nose downangle greater than 4° with respect to towed semi-trailer. Damage to vehicle or loss of control couldoccur.a.Pull secondary lockrelease handle (1) before releasing pri-mary lock release handle (2) to uncou-ple the trailer.2-98